A polyurethane resin is usually produced by reaction of polyisocyanate with an active hydrogen group-containing compound, and is, for example, widely used in various industrial fields such as coating materials, coatings, adhesive materials, pressure-sensitive adhesive materials, and elastomers.
As the polyisocyanate used in the production of the polyurethane resin, for example, xylylene diisocyanate and a derivative thereof, and hexamethylene diisocyanate and a derivative thereof are known. It is also known to use a mixture of them.
The polyisocyanate is, for example, used as curing agents for coatings and adhesives. To be specific, for example, a curing agent containing a polyol modified product of xylylene diisocyanate of 30 to 90 weight %, and a biuret modified product and/or a trimer of hexamethylene diisocyanate of 10 to 70 weight % is proposed (ref: for example, Patent Document 1).
According to the curing agent, a two-component curable polyurethane composition having excellent adhesion properties, acid resistance/alkali resistance, solvent resistance, contamination resistance, and weather resistance can be obtained.